- find a clean way to mmap the framebuffer, just returning the
physical
address works on macppc but not on other architectures. Problem
is, that

we cannot rely on the address being a bus address - on macppc it is,
but for instance on sparc64 it's not.

There is a bus_space_mmap() and a bus_space_vaddr(), so if you can
encapsulate everything within a bus_space_tag_t / bus_space_handle_t,
you should be good.

Yes, it would be nice to have prop types for those sorts of things.
I have been considering how to extend proplib at run-time with custom
types (that would allow, for example, putting device_t's into a
dictionary).